Ebola is not an airborne virus, the CDC says on its website, meaning it cannot spread by, for example, sitting next to an infected person in a bus or on a train. Ebola in general does not spread via water or food, or insects like mosquitoes, although it may be spread by eating bushmeat or coming into contact with infected animals.

The virus can only be spread among humans by a patient who is already showing symptoms, such as fever, flu-like body pain, abdominal pain, diarrhea and vomiting. To become infected, a person needs to come into contact with an infected person’s bodily fluids such as blood, sweat, vomit, feces, urine, saliva or semen.

The virus can be spread through direct contact with broken skin or mucous membranes. Health workers wear protective gear such as masks, goggles and gloves to avoid this kind of contact.

The current Ebola epidemic is the first to have spread outside the African continent. Before this year, Ebola outbreaks have mostly been confined to remote parts ofAfrica.